[OpenLayers-Dev] Bug in rendering features with cluster strategy

[Tim Schaub]

Eric Lemoine wrote:
> Tim, what about this case: feature is selected then is *removed* from
> the layer.  Eventually the feature handler triggers "mouseout", which
> makes the select feature control call drawFeature for a feature which
> isn't in the layer. Eric

layer.removeFeatures sets feature.layer to null

The Feature handler shouldn't handle any features with a non-truthy layer.

> 
> 2008/11/4, Tim Schaub <tschaub at opengeo.org>:
>> Hey-
>>
>> Eric Lemoine wrote:
>>> Yes. Especially since drawFeature is often called from addFeatures,
>>> where we're assured that the feature is in the layer. So, instead, we
>>> may want to change the select feature control so that it calls
>>> drawFeature only if, in the case of selection, the feature is in the
>>> "features" array, and in the case of unselection, the feature is in
>>> the "selectedFeatures" array. What do you think? Eric
>>>
>> The problem is in the Feature handler.  We destroy features, but
>> references to them are still truthy.  Since the destroy code sets the
>> layer property to null, one check of an undestroyed feature is to check
>> feature.layer.
>>
>> See http://trac.openlayers.org/attachment/ticket/1806/destroyed.patch
>>
>>> 2008/11/4, Tim Schaub <tschaub at opengeo.org>:
>>>> Hey-
>>>>
>>>> Ivan Grcic wrote:
>>>>> OK... i found it..inside Layer.Vector...now the question is: should i
>>>>> put something like this:
>>>>>
>>>>> if (OpenLayers.Util.indexOf(this.features, feature) != -1){
>>>>>
>>>>> inside drawFeature: function(feature, style) {
>>>> Nope.  Making drawFeature that safe at the expense of iterating through
>>>> every feature with every draw is a mistake.
>>>>
>>>>> or inside every other function inside Layer.Vector that uses
>>>>> drawFeature function?
>>>>>
>>>>> When I put it here:
>>>>>
>>>>>     drawFeature: function(feature, style) {
>>>>> -->	if (OpenLayers.Util.indexOf(this.features, feature) != -1){
>>>>> ..
>>>>> ..
>>>>>      }
>>>>> }
>>>>>
>>>>> it works pretty fine for me :) Eric?
>>>>>
>>>>> On Mon, Nov 3, 2008 at 9:53 AM, Ivan Grcic <ivan.grcic at geofoto.hr>
>>>>> wrote:
>>>>>> Yup, its not Cluster Strategy...
>>>>>> http://trac.openlayers.org/ticket/1806#comment:2
>>>>>>
>>>>>> On Mon, Nov 3, 2008 at 9:11 AM, Eric Lemoine <eric.c2c at gmail.com>
>>>>>> wrote:
>>>>>>> Hi.
>>>>>>>
>>>>>>> Yes, this looks like a bug in OpenLayers.
>>>>>>>
>>>>>>> I'm under the impression that this isn't a bug in the cluster strategy
>>>>>>> but either in Layer.Vector or in Control.SelectFeature. Indeed, I
>>>>>>> think SelectFeature calls layer.drawFeature on feature
>>>>>>> selection/unselection without checking whether the feature is in the
>>>>>>> layer. And i'm saying this may be a bug in Layer.Vector because it may
>>>>>>> be that drawFeature should be responsible for checking whether the
>>>>>>> feature is in the layer before actually drawing it.
>>>>>>>
>>>>>>> This is just coming from the top of my head so i may be wrong, but i'm
>>>>>>> feeling this is a good track to follow :)
>>>>>>>
>>>>>>> Eric
>>>>>>>
>>>>>>> 2008/11/2, Ivan Grcic <ivan.grcic at geofoto.hr>:
>>>>>>>> Hi list,
>>>>>>>>
>>>>>>>> i discovered a bug while developing my OL application, in cluster
>>>>>>>> strategy class.
>>>>>>>>
>>>>>>>> Bug occurs when you hover over one feature that represent a cluster
>>>>>>>> (or externalGraphic or like in cluster example - vector circle
>>>>>>>> http://openlayers.org/dev/examples/strategy-cluster.html)
>>>>>>>>
>>>>>>>> When you zoom in/out while that feature-cluster is selected (by
>>>>>>>> quickly double-clicking or easier using scroll on ur mouse), on next
>>>>>>>> zoom that cluster is rendered (stays on screen) together with newly
>>>>>>>> created clusters! And clearly it shouldnt be there. The old
>>>>>>>> ("phantom") cluster is not selectable, as he doesnt exist on the new
>>>>>>>> zoom level..he just stays there on screen...annoying me :)
>>>>>>>>
>>>>>>>> As you zoom in again and again, phantom clusters always render,
>>>>>>>> always
>>>>>>>> at the same position in the map div...
>>>>>>>>
>>>>>>>> Please confirm that this is a bug, im going crazy here with this one
>>>>>>>> :|
>>>>>>>>
>>>>>>>> --
>>>>>>>> Ivan Grcic
>>>>>>>> _______________________________________________
>>>>>>>> Dev mailing list
>>>>>>>> Dev at openlayers.org
>>>>>>>> http://openlayers.org/mailman/listinfo/dev
>>>>>>>>
>>>>>> --
>>>>>> Ivan Grcic
>>>>>>
>>>>>
>>>> --
>>>> Tim Schaub
>>>> OpenGeo - http://opengeo.org
>>>> Expert service straight from the developers.
>>>> _______________________________________________
>>>> Dev mailing list
>>>> Dev at openlayers.org
>>>> http://openlayers.org/mailman/listinfo/dev
>>>>
>>
>> --
>> Tim Schaub
>> OpenGeo - http://opengeo.org
>> Expert service straight from the developers.
>> _______________________________________________
>> Dev mailing list
>> Dev at openlayers.org
>> http://openlayers.org/mailman/listinfo/dev
>>


-- 
Tim Schaub
OpenGeo - http://opengeo.org
Expert service straight from the developers.